Radioactivity, for example nuclear energy, is used as a core energy source today for its very high utility value and a wide variety of applications. However, in the process of using the nuclear energy, a radioactive material is released that can threaten the lives of people and therefore, its use requires thorough management. Accordingly, for the radiation workers who work outside the nuclear power plant as well as inside the nuclear power plant, it is regulated by the Nuclear Safety Act that the dose limit be managed at 50 mSv or less per year cumulative and at 100 mSv or less for 5 years cumulative. Related authorities require that workers be provided with protective equipment to prevent the workers from exposure to radiation, and that facilities such as radiation shielding facilities, ventilation and defense facilities and surveillance facilities be arranged for the safety of radiation workers. In addition, the dose limit of the worker is managed by regularly reading the exposed dose of the radiation worker. The exposed dose readings are intended to be read at least quarterly (in the case of TLDs), but the period may be shortened as necessary.
Accordingly, the radiation worker is obliged to wear a legal dosimeter (a dosimeter that is legally recognized as a tool for measuring radiation dose), which is a means for measuring the radiation dose (exposed dose). The legal dosimeter is a tool used to measure and evaluate the exposed dose of an individual, allowing a radiation worker who is exposed to radiation to check the exposed dose by reading the legal dosimeter. Currently, the most widely used legal dosimeters are thermal luminescence dosimeter (TLD) and optical stimulation luminescence dosimeter (OSL), and all the legal dosimeters including the TLD and OSL are analog-type dosimeters that cannot be immediately numerically checked, but require separate reading tasks.
By reading these legal dosimeters, the annual personal average exposed dose of the radiation worker is continuously maintained so that it does not exceed the dose limit. As described above, thorough management is very important for the safety of the radiation workers who work with and around the radioactive material.
While the legal dosimeter described above has an advantage in that the exposed dose can be checked accurately through readings, it has a disadvantage in that it is impossible to check the numerical value without going through an intermediate process of reading with an analog verification method. In particular, since the act of reading is not carried out every day (it is usual to read quarterly or monthly), instantaneous exposed dose and cumulative exposed dose cannot be checked in real time, which is not enough to prevent exposure to excessive radiation or respond quickly and take action in case of accidents.
For this reason, workers had to wear assistant dosimeters separate from the legal dosimeter, in order to check the instantaneous exposed dose value in real time to ensure safer operation.
However, in spite of the advantage of the assistant dosimeter, it is inconvenient for the worker to wear another dosimeter (i.e., assistant dosimeter) in addition to the legal dosimeter he/she is already wearing, and for this reason, the worker sometimes neglects his/her duty to wear the assistant dosimeter during the operation. This is a very dangerous act because the worker is exposing himself/herself to a risk of radiation accident without having any countermeasures.
In addition, while it is legally required to wear the legal dosimeter as well as assistant dosimeter, with the dosimeter alone, there is no way to know if a worker has actually worn the legal dosimeter. By taking advantage of this, there are cases where: a plurality of workers share one single legal dosimeter; workers do not wear their own legal dosimeters, but wear the legal dosimeter of the others; or workers do not wear the legal dosimeters at all during operation, thus intentionally or unintentionally contribute to the manipulation of the data about the exposed dose values.
Whether it is intended or not, it is true that the workers in many cases do not usually wear the legal dosimeters at work, deteriorating the reliability of the data of the actual exposed dose reading of the workers.
Accordingly, there is a need for a device that can provide worker safety measures, which can prevent workers from being exposed to an accidental exposure at work, and increase the reliability of exposed dose data.
Examples of the prior arts of the present invention can be found in patent documents including KR Patent No. 10-0942419 (Patent Document 1), entitled “The Apparatus of Reforming a Dosimeter”, and KR Patent No. 10-1450169 (Patent Document 2), entitled “Automated Dosimetry Record and Transmission System Using the Automated Dosimetry Record and Transmission Method Using the Automated Dosimetry Record”.